Culebra Island is beautiful. I just got back to Canada from Puerto Rico. I was there for a month. I loved Culebra so much I went back twice. On my second trip I spent two nights camping at Playa Flamenco. I paid $20 USD per night for a sweet little camping spot (section E). I saw turtles, amazing, colourful fish and met some wonderful people. The snorkelling was okay in terms of being able to see under water but the reefs are not healthy. There was plenty of coconut to pick to drink the water inside and eat the meat. I found passion fruit, mangoes (not ripe), almonds (not ripe) and another really weird looking fruit I don’t know the name of. While I didn’t enjoy the main island of Puerto Rico as much as I’d hoped, I would go back to Culebra if the opportunity ever arose. I made some friends (Perri and Hector–owners) at a little place in town called, “Aqui Me Quedo” who I will never forget their kindness and hospitality.
Since airline reservation requests are often made by city-pair (such as "show me flights from Chicago to Düsseldorf"), an airline that can codeshare with another airline for a variety of routes might be able to be listed as indeed offering a Chicago–Düsseldorf flight. The passenger is advised however, that airline no. 1 operates the flight from say Chicago to Amsterdam, and airline no. 2 operates the continuing flight (on a different airplane, sometimes from another terminal) to Düsseldorf. Thus the primary rationale for code sharing is to expand one's service offerings in city-pair terms to increase sales.